android 中通知消息中打开activity带参数的问题

在activity中获取的参数始终是空的，一开始在PenddingIntent的最后一个参数用0

Intent intent=new Intent(getApplicationContext(),Main2Activity.class);Log.d("notice",drugname);intent.putExtra("drug",drugname);PendingIntent pendingIntent= PendingIntent.getActivity(getApplicationContext(),0,intent,0);

导致无法正确获取参数

PendingIntent pendingIntent= PendingIntent.getActivity(getApplicationContext(),0,intent,PendingIntent.FLAG_UPDATE_CURRENT);
修改了第四个参数后能够正确获取